I forgot the size you would have to paint. You could buy a gallon, or a case of spray cans for real life size army vehicle restoration like I use on my jeeps. Gillesipi 24087 is sold by rapco. Google it amd you will find it. Close to the right color, a smidge on the green side but would work great on a tank your size.
According to the research Steve Turchet did, a MV guru, the color was always the same through wwii. A very dark olive drab that could appear brwon in some light, or green in some light, and could also be mistaken for black with very little light it was so dark. This was true from 30s through wwii. What changed was the pigment formula to make the paint a few times over that span. The big change came in 44 when it switched from lusterless(flat) to semi gloss. The application of the semigloss makes the color appear much darker than the flat, even though the pigment is the same. I painted some test samples today trying to get an exact scintific formula measured by volume and sprayed samples with gloss when I was done, which has a drastic effect on color.
as for the travel lock, you have i assume a 105 travel lock, which really aint quite right for the 76. You need the shorter 75mm travel lock. Do they make that for your model?
yes, cut a groove into the rear deck, and put a seam cover over most of the groove per the picture, and rearrange the the bolts.